A single-cylinder rotary compressor shown in FIG. 1 in the related art has advantages of simple machining and good performance and is applied widely to a room air conditioner. However, since vibration amplitude of the compressor is determined basically by a size of a torque fluctuation when the compressor is working, the larger vibration of the compressor not only seriously affects reliabilities of the compressor and the air conditioner, but also causes serious noise problems.
Due to adopting single-cylinder eccentric compression technologies, the torque of compressed gas changes greatly during a usage of the single-cylinder rotary compressor, as “Torque A” shown in FIG. 4. Furthermore, the vibration of the compressor is increased with an increase of a compressor displacement, and the noise of the air conditioner is increased, too, thus affecting the usage.
Compared with the single-cylinder compressor in the art, a double-cylinder rotary compressor with the same displacement has an upper air cylinder and a lower air cylinder, two eccentric portions of a crankshaft thereof are configured to form 180°, and the torque of the compressed gas changes much smaller (which is shown as “Torque B” in FIG. 4), thus reaching a good vibration performance. However, the double-cylinder rotary compressor, compared with the single-cylinder rotary compressor, has disadvantages of a large amount of components and parts and dramatically increasing manufacturing costs. In addition, due to adding a set of compression assembly, friction pairs are increased, thus making friction losses to increase.